1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to apparatus and methods for in situ formation of luminal prostheses within a body lumen, such as a blood vessel.
Coronary artery disease is the leading cause of death and morbidity in the United States and Western society. In particular, atherosclerosis in the coronary arteries can cause myocardial infarction, commonly referred to as a heart attack, which can be immediately fatal or, even if survived, can cause damage to the heart which can incapacitate the patient.
While coronary artery bypass surgery can be an effective treatment for stenosed arteries resulting from atherosclerosis or other causes, it is a highly invasive, costly procedure, which typically requires substantial hospital and recovery time. Percutaneous transluminal coronary angioplasty, commonly referred to as balloon angioplasty, is less invasive, less traumatic, and significantly less expensive than bypass surgery. Heretofore, however, balloon angioplasty has not been considered as effective a treatment as bypass surgery. The effectiveness of balloon angioplasty, however, has improved significantly with the introduction of stenting which involves the placement of a scaffold structure within the artery which has been treated by balloon angioplasty. The stent inhibits abrupt reclosure of the artery and has some benefit in inhibiting subsequent restenosis resulting from hyperplasia. Recently, experimental trials have demonstrated that the coating of stents using anti-proliferative drugs, such as paclitaxel, can significantly reduce the occurrence of hyperplasia in angioplasty treated coronary arteries which have been stented with the coated stents. Stents are also used to treat blockages of peripheral blood vessels, including those in the neck, head, abdomen and legs.
While the combination of balloon angioplasty with drug-coated stents holds great promise, significant challenges still remain. Of particular interest to the present invention, the treatment of extended or disseminated disease within an artery remains problematic. Most stents have a fixed length, typically in the range from 10 mm to 30 mm, and the placement of multiple stents to treat disease over a longer length requires the use of multiple stent delivery catheters. Moreover, it can be difficult to stent an angioplasty-treated region of a blood vessel with the optimum stent length.
For these reasons, it would be desirable to provide improved stents, stent forming apparatus and methods, stent delivery systems, stenting methods, and the like, for the treatment of patients having coronary artery disease, as well as other occlusive diseases of the vasculature and other anatomical structures. In particular, it would be desirable to provide stents, stent forming apparatus and methods, stent delivery systems, and methods for the treatment of disseminated and variable length stenotic regions within the vasculature. For example, it would be desirable to provide a practical method which permits a physician to tailor the length of the stent delivered to a treatment location while the delivery apparatus is adjacent to the treatment location, rather than having to deliver a stent having a predetermined length. More specifically, it would be desirable to provide apparatus, systems, and methods for facilitating the delivery and in situ formation of stents and other prostheses to blood vessels or other target body lumens. Such apparatus, systems, and methods should be suitable for delivery and in situ formation of individual stents or prostheses having lengths ranging from very short (typically as short as 3 mm or shorter) to relatively long (typically as long as 100 mm or longer), which lengths may be determined for a subject stent during the course of the stent delivery and in situ formation. Such apparatus, systems, and methods should also be capable of delivering and forming multiple individual stents at multiple treatment locations during a single interventional procedure (i.e., without fully withdrawing the catheter from the patient). At least some of these objectives, and others, will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 6,258,117 B1 describes a stent having multiple sections connected by separable or frangible connecting regions. Optionally, the connecting regions are severed after the stent structure has been implanted in the blood vessel. U.S. Pat. Nos. 5,571,086; 5,776,141; and 6,143,016 describe an expandable sleeve for placement over a balloon catheter for the delivery of one or two stent structures to the vasculature. U.S. Pat. No. 5,697,948 describes a catheter for delivering stents covered by a sheath.
U.S. Pat. No. 5,059,211 describes an expandable absorbable stent. U.S. Pat. No. 5,147,385 describes methods for using stents that are hollow, cylindrical structures made of synthetic substance that becomes plastic and malleable in a temperature range of from 45° to 75° Celsius. U.S. Pat. Nos. 5,213,580 and 5,947,977 describe processes for paving or sealing interior surfaces of body vessels or organs by entering the interior of the vessel or organ and applying a polymer to the interior surfaces thereof. U.S. Pat. No. 5,670,161 describes an expandable, biodegradable stent. U.S. Pat. No. 6,607,553 describes an expandable stent that is coated with a radiation-absorbing material. U.S. Pat. No. 6,039,757 describes a fenestrated stent formed in a body lumen. U.S. Pat. No. 6,623,519 describes an endoluminal stent containing a hollow passageway for circulating fluids to treat vascular walls affected with malignant growths or experiencing restenosis.